Piano construction



Oct. 25, 1949. R, W` E, SPERRY .E1-AL 2,486,338

PIANO CONSTRUCTION Filed Sept. 28, 1946 3 Sheets-Sheet 1 &/

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PIANO CONSTRUCTION 3 Sheets-Sheet 2 Filed Sept. 2,8, 1946 INVENTORS.

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PIANO CONSTRUCTION Filed sept. 28, 194e 3 Shee'ts-sheet s INVENTORS. FWF/f 144 f". ff/Wwf JH cK 6', Hoff/f,

Patented Oct. 25, 1949 PIANO CONSTRUCTION Ralph W. E. Sperry and Jack C. Horth, De Kalb,

Ill., assignors to The Rudolph Wurlitzer Company, De Kalb, Ill.

Application September 28, 1946, Serial No. 700,102

3 Claims.

This invention relates to the construction of an upright piano, particularly that type of piano generally known as a spinet, and has particularly to do with the construction of the back structure of the piano, the mounting of the sounding board, the string plate stamped Of sheet metal, and the direct support of the key bed thereon, all as a complete unit about which any desired piano casing may be designed and mounted.

One feature of the invention resides in the form and construction of a stamped sheet metal string plate as distinguished from the usual casting, and wherein the stamping is formed with flanged struts and provided with cross bars or ribs to provide reinforcement against warpage such that it may be produced from dies in mass production to precise form and dimensions. Said string plate further has the advantage of having provided thereon a series of hitch pin plates for the strings as well as a panel provided with locating holes for the tuning pins. By reason of this structure of string plate substantial economy may be practiced, as well as providing for accuracy and permanency in the construction and assembly of the piano.

Another feature of the invention relates to the back structure of the unit incorporating steel tubing and channel pieces embodying therein strength, rigidity, and dimensional stability to a greater measure than possible in the conventional wooden structures, and at a lesser weight. Such metal back structure also results in increased manufacturing facility with consequent lower cost, such as to produce greater resistance to the elects of exposure to adverse climatic conditions.

A further feature of the invention resides in the structural mounting on the metallic back structure and string plate of a key bed having its sole support therein without depending upon the piano casing therefor. Thus the key bed may be stamped of sheet metal and directly secured to the metal back structure as a unit entirely independent of the piano casing in which the unit is mounted. With this construction all parts of the playing mechanism, except the pedals and trap work, may be secured together as a standard production unit, irrespective of varying styles of piano case. Thus many different styles of piano case may be built around this structural unit without effecting the functional parts oi the piano, adjustment or regulation of the playing mechanism. With this construction a much improved control of accuracy in manufacturing and assembly results in greater manufacturing eiciency, quality, and uniformity of the piano.

The full nature of the invention will be understood from the accompanying drawings and the following description and claims:

. Fig. l is a perspective View of the piano unit.

Fig. 2 is a perspective view showing the back of the unit.

Fig. 3 is a perspective view of the front face of the stamped steel string plate.

Fig. 4 is the same as Fig. 3 showing the reverse side of the string plate.

Fig. 5 is a perspective view of the unit taken on the line 5--5 of Fig. 2 with a portion broken away.

Fig. 6 is a perspective view taken on the line 6-6 of Fig. 2 with a portion broken away.

Fig. 7 is a perspective view taken on the line 'I--l of Fig. 2 with a portion 'broken away.

Fig. 8 is a perspective view showing a portion of a modified form of structural unit in respect to the mounting of the key bed.

Fig. 9 is a perspective view with parts broken away of the structure shown in Fig. 8.

Fig. 10 is a perspective view of a section taken on the lines Ill-Ill of Fig. 9.

In the drawings there is shown an upright piano unit comprising a backboard, sounding board, string plate, and key bed structurally secured together as a unit for embodiment in any suitable piano casing without relying upon any part of the casing for structural support or mounting of these elements.

For purpose of illustration there is shown in the drawings a backboard IIJ, sounding board Il', steel string plate I2, and the key bed I3 secured to the backboard and string plate by the end brackets III.

The backboard comprises a series of uprights I5 formed of steel tubing. The upper and lower ends of the uprights extend into clamping engagement with the upper steel.channel I6 and the lower steel channel I1, respectively. The uprights are preferably in the form of steel tubing square in cross section arranged with their ends snugly tting within the upper and lower steel channel bars I 6 and Il. Said uprights are welded in place within the channel bars, each of which have their free edges flanged inwardly at I8 intermediate the respective uprights. The end uprights I9 are in the form of channel pieces having embedded therein a wood filler 20 protruding slightly therefrom along the edge for convenient securing thereto of the piano case in which the unit is mounted.

Along the top of the back structure there is provided a wooden wrest plank ZI. Along the sides and bottom of the back are provided filler strips 22, which are preferably of wood. The sounding board 23 is mounted in spaced relation to the back structure clamped to said ller strips by the retaining strips 24 and 25. For this purpose, the top and bottom metal channel bars I6, II are provided with internally threaded studs 26, each adapted to receive a retaining screw 2l. Said retaining screws not -only clamp the sounding board to the back structure in spaced rela- 3 tion thereto but also extend through and secure in place thereon the string plate |2.

The string plate as shown in Figs. 3 and 4 is stamped from sheet steel with the struts 29 ilanged along their edges as indicated at 30 and with similar reinforcing flanges 3| formed inwardly from the front of the plate. The upper portion of the plate, however, is formed with reversely directed iianges 32, said end flanges 32 terminating in a connecting bracket 33 for the casing. On the forward face of the plate there are a series of apertures 34 drilled in the tuning pin panel 35 through which the tuning pins for the piano strings extend. Said panel is bordered along the lower edge thereof with a stamped tension bar 36 reinforced with a series of short webs 3l' formed at right angles thereto.

Fig. 3 is a View of the front face of the plate over which the strings are mounted, Fig. 4 being a back View thereof. The hitch pins 38 are separately formed upon the hitch pin plates 39 which are welded along the front surface of the proper struts 29, so that the strings 40 extend from their respective hitch pins 38 to their respective tuning pins 4| over the tension bars 36 and bridges 42 (Fig. 5). The plate thus formed is further reinforced by the diagonally disposed ribs in the form of cross bars 44, 45, and 46 welded to the front face of the plate, the cross bars 44, 46 dening the area of the bass strings and the cross bars 45, 46 defining the areas of the low treble and high treble strings. The string plate is anchored to the back structure by the screws 21 along the upper and lower edges thereof, and intermediately by the bolts 4l which are screwed into the sockets 48 Which in turn pass through openings 49 provided in the sounding board 23 with their rear ends welded to the sides of the steel uprights I5.

Reference being had to Fig. 1, the key bed |3, which` may be of lwood or' stamped steel, is formed with a balance rail 50 extending longitudinally thereof having upwardly extending hinge pins and the usual upstanding guide pins 52 whereby the keys may be hingedly supported and located thereon. As shown, the key bed is permanently secured to the end flanges 32 of the string plate |2 and the back structure.

In the modified form shown in Figs. 8, 9, and a sheet metal key bed ||3 is secured to the back structure as a unit` by a vertically extend-` ing end panel H9 stamped of sheet metal. Said supporting end panel is preferably welded along its rear edge to the steel end post I9 of the back structure, and is formed with a cap |20 welded over the end of the top steel channel member I6, The end panel ||9 extends forwardly and is curved inwardly terminating in an inwardly turned ange |2|, which is notched at |22 to receive and interlock with the key bed ||3. Each end of the key bed extends inwardly within the panel ||9 so as to abut thereagainst for direct Welding thereto.

From the foregoing it will be observed that the functional structure yof the piano comprises a unitary chassis ready to receive the action and keys and be incorporated within any suitable design. of piano casing. By reason of the structural steel assembly of the units, they may be mass produced with dimensional accuracy, and with unusual resistance to climatic conditions.

We claim:

1. In an upright piano, a structural unit comprising a series of spaced uprights formed of steel tubing, a metal channel member embracing the upper ends of said uprights and secured thereto,

a companion channel member embracing une lower ends of said uprights and secured thereto, said uprights and channel members forming a back structure, a sounding board extending over and in spaced relation to said back structure, a steel string plate extending over and spaced from said sounding board, a wrest plank embracing the upper edge of said sounding board extending along the upper channel member, filler strips embracing the sides and the lower edge of said sounding board extending vertically along the side tubing members and extending horizontally along the lower channel member, and means for securing said string plate directly to said back structure through said sounding board free from engagement therewith.

2. In an upright piano, a structural unit comprising a series of spaced uprights formed of steel tubing, a metal channel member embracing the upper ends of said uprights and secured thereto, a companion channel member embracing the lower ends of said uprights and secured thereto, said uprights and channel members forming a back structure, a sounding board extending over and spaced relation to said back structure, a steel string plate extending over and spaced from said sounding board, a wrest plank embracing the upper edge of said sounding board extendingalong the upper channel member, filler strips embracing the sides and the lower edges of said sounding board extending vertically along the end uprights and extending horizontally along the lower channel member, a plurality of internally 'threaded studs secured to said back structure extending forwardly therefrom, and screw members for threaded engagement with said studs extending through said string plate for securing it to said back structure, the intermediate studs passing through apertures in said sounding board free of engagement therewith.

3. In a piano, a back structure comprising a series of spaced uprights formed of square steel tubing, a metal channel member extending transversely of and embracing the upper ends of said ,Y uprights, a channel member extending transversely of and embracing the lower ends of said uprights, said channel members being permanently secured to said uprights and having their free edges flanged inwardly intermediate thereof, and a pair of end posts having their upper and lower ends embraced and secured at the ends of said channel members, said end posts each being in the form of a channel upright with a wood ller secured therein with one face exposed therefrom to provide said back structure with wooden end surfaces.

RALPH W. E. SPERRY.

JACK C. HORTH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 197,332 Chickering Nov. 20, 1877 359,517 Wing Oct. 12, 1886 1,699,561 Collen Jan. 22, 1929 1,990,574 Story Feb. 12, 1935 FOREIGN PATENTS Number Country Date 9,373 Great Britain 1893 355,816 Great Britain Aug. 3l, 1931 499,697 France Nov. 26, 1919 

